The Data Control Block (DCB) parameter details the physical characteristics of a dataset. This parameter is required for datasets that are newly created in the job step. LRECL is the length of each record held within the dataset. RECFM is the record format of the dataset.

The DISP parameter is used to describe the status of the dataset, disposition at the end of the job step on normal and abnormal completion. DISP is not required in a DD statement only when the dataset gets created and deleted in the same job step (like the temporary datasets). Syntax − DISP = (status, normal-disposition, abnormal-disposition)

The DSN parameter refers to the physical dataset name of a newly created or existing dataset. The DSN value can be made up of sub-names each of 1 to 8 characters length, separated by periods and of total length of 44 characters (alphanumeric).

Based on the time duration and the number of resources required by the job, companies assign different job classes. These can be visualized as individual schedulers used by the OS to receive the jobs. Placing the jobs in the right scheduler will aid in easy execution of the jobs. Some companies have different classes for jobs in test and production environment. Valid values for CLASS parameter are A to Z characters and 0 to 9 numeric (of length 1). Following is the syntax − CLASS=0 to 9 | A to Z

When the job reaches its highest priority, it is taken up for execution from the job queue. The JCL is read from the SPOOL, the program is executed and the output is redirected to the corresponding output destination as specified in the JCL.

Identifiers are two slashes (//) starting from column number 1. All JCL statements starts with identifiers except for two exceptions – For a delimiter statement, /* starting in col 1 and for a comment statement, //* starting at col 1

JCL stands for Job Control Language which provides the specifications necessary to process a job. It is a set of control statements which provides the specifications necessary to process a job. It is a interface between programs & MVS operating system.

A job time-out error can occur when the program takes more time than the time limit for the specified class. This is called a S322 abend. This error is encountered when there are some looping errors in the program and it does not reach completion.

If the data processed in the program is genuinely huge and needs more time than the class limit, then the TIME parameter can be coded as TIME = 1440 to get infinite time until job completion.

When it is defined with DISP = (NEW,KEEP) at the time of creation. In case of a GDG, least recent generation is uncataloged if the GDG base had been defined with NOEMPTY parameter when the LIMIT is reached. All generations are uncataloged when coded with EMPTY.

Dummy DD statements, data card specifications, PROCs, JOB, PROC statements cannot be coded within an INCLUDE member. An INLCUDE statement can be coded within an INCLUDE member and further nesting can be done up to 15 levels.

The varying portion of the JCL can be specified using symbolic parameters in the JOB and the static parts can be specified in the PROC. For example, if the file name changes for every JOB that uses the PROC, then the varying portion of the file name can be coded in JCL using symbolic parameter.